San Francisco low-wage earners have been warned—in an advertising display that is hard to ignore—that they will be replaced by iPads if local voters approve a $15-an-hour minimum wage in November. The current wage is $10.74 an hour.

PandoDaily couldn’t help but write about the ad campaign after a huge billboard went up on a downtown building next door. The sign shows a hand holding an electronic device that says, “Hello, may I take your order?” The implication is that fast-food workers will bear the brunt of a pay raise.

Of course, they aren’t the only ones making poverty wages. PEW Research Center reported that 3.55 million people nationally earned the minimum wage or less in 2012, but less than half of them were in food service or related occupations. More than half a million were in sales and related fields, 268,000 provided personal care and services, 240,000 toiled in transportation and “material moving occupations, 231,000 were in maintenance, 227,000 provided office and administrative support services.

Now that many companies classify their employees as contractors to avoid providing them benefits, you never can tell when you’re talking to a minimum-wage worker. More than 110,000 are in professional and related occupations, 109,000 are in “production,” 100,000 provide healthcare support, 49,000 are in protective services, and 40,000 are in farming, fishing and forestry.

Granted, there may not be many farmers and fishermen in San Francisco, but it’s a good bet that it will be hard to replace all the other minimum wage workers with iPads. That includes 39,000 construction, installation and repair workers nationally and 33,000 “management, business and financial operations” folks.

Even with small increases in the minimum wage in municipalities, states and the nation, real purchasing power of these low-wage earners hasn’t increased in four decades and is below its peak in the 1960s. Keynesian economists argue that raising the minimum wage puts more money in the economy and stimulates growth. Conservatives want government to keep its hands off their money and see no benefit from having their wishes ignored.

The billboard is sponsored by Badideasca.com, which is a project of the Employment Policies Institute (EPI). The conservative non-profit “research organization” does a lot of work for the restaurant industry, according to Pando. The institute was featured in an article by Salon last November that ripped the media for accepting claims by industry public relations firms that they are respectable think tanks.

EPI was quoted extensively in the press last year as offering authoritative rebuttal to a study out of the University of California, Berkeley, which said low wages in the fast-food industry cost taxpayers $7 billion a year in social support. Salon found EPI shared offices with Berman & Co., a public relations firm that represents the tobacco industry, hotels, beer distributors, taverns and restaurant chains.

According to Sourcewatch, “Berman & Co. operates a network of dozens of front groups, attack-dog web sites, and alleged think tanks that work to counteract minimum wage campaigns, keep wages low for restaurant workers, and to block legislation on food safety, secondhand cigarette smoke, and drunk driving and more.”

Los Angeles got a taste of EPI’s thoughtful advertising when a billboard popped up sporting a giant tongue-wagging mugshot of entertainer Miley Cyrus that asked, “Why is Miley Cyrus so twerked off?” The answer: “Maybe it’s because so many California teens will lose their jobs when the minimum wage goes up.”

Many of those teens have already lost their jobs to adults who previously lost theirs.

San Francisco’s November ballot measure will ask voters to raise the minimum wage gradually over the next four years to a national high of $15 an hour in 2018. Labor activists had pushed to get that done by 2017.